The background of the invention will be discussed in two parts.
1. Field of the Invention
This invention relates to electrical distribution systems, and more particularly, to a lighting system having lighting fixtures selectively attachable to a track-like conductor assembly, and the connector devices used in such systems.
2. Description of the Prior Art
Electrical distribution systems, and the lighting fixtures used therewith have typically been of a fixed nature. Numerous attempts have been made to provide a measure of flexibility in electrical distribution systems, and particularly with reference to placement of lighting devices. Some of these attempts have utilized specially configured insulated conductor members, positioned or retained in specially configured housings or channels, with plug members or lamp fixture assemblies having prongs or piercing members adapted for penetrating the insulation layer of the conductors upon assembly.
In more recent years, electrical distribution systems for lighting have been developed utilizing a "track" arrangement in which a conductor assembly, enclosed in or formed in a track, enables the placement of any number of a plurality of fixtures at any one of a number of locations along the track. Such systems are referred to as track lighting systems and have the advantage of being able to place illumination where needed, as needed, without complete rewiring behind fixed partitions, walls and ceilings. Such systems have been adopted in commercial, office, manufacturing and retail establishments where flexibility of positioning of lighting sources is important as the need arises for relocation of displays, equipment or walls. In more recent years, such systems have found their way into residential lighting, as functional or decor illumination.
One such early light fixture mounting arrangement is shown and described in U.S. Pat. No. 1,131,724, entitled "Electric Lamp Socket", issued March 6, 1915, to Mills, the socket including a pair of spaced pin members extending from the end thereof opposite the lamp engaging opening, the pins being bent at an angle to the end surface for piercing a two conductor cable at an angle to thus make electrical connection while retaining the socket relative to the cable.
Another mounting arrangement is shown and described in U.S. Pat. No. 1,287,542, entitled "Lamp Mounting" issued to Whitney on December 10, 1918, the mounting including a lamp fixture for attachment to a pair of parallel insulated wire strands. The mounting includes hook shaped edges for engaging the conductors with first and second pin portions adapted for piercing the insulation of each conductor for providing electrical connection thereto.
U.S. Pat. No. 2,162,545, entitled "Electric Fixture", issued June 13, 1939 to Benander et al, the device including an electrical plug arrangement with the housing thereof configured for a dual purpose. One configuration includes blade receiving openings with the receptacle being attachable to a conductor cable for use as an extension, with the second configuration including contact arrangments which enable the same contacts to serve as blades for being received within a plug as well as contacts for the blades of another plug. Electrical connection of a cable to the blade contacts is by means of pins for piercing the insulation layer of the cable.
U.S. Pat. No. 2,274,136, entitled "Continuous Outlet Construction" issued Feb. 24, 1942 to Frank et al, and depicts another arrangement for providing some flexibility to an electrical distribution system. An electrical conductor is formed as a generally C-shaped channel member with electrical conductors or bus bars embedded at the bent portions thereof, with a plug member having a pair of coplanar blades adapted for being received within the open slot portion for engaging the bus bars.
Another lamp mounting arrangement is shown and described in U.S. Pat. No. 3,130,921, entitled "Vehicle Lamp Mounting", issued Apr. 28, 1964 to Morgan. The mounting system includes an electrically conductive channel member attachable to a vehicle with a first channel portion receiving a single conductor strip. A lamp assembly is insertable within the channel member with a first conductor thereof configured and positioned for piercing the insulation of the conductor carried by the strip, with the second conductor of the lamp assembly spring biased for electrically contacting a portion of the channel member.
Another such vehicle lamp mounting arrangement is shown and described in U.S. Pat. No. 3,225,185, entitled "Mounting for Marker Light", issued to Bertolini et al on Dec. 21, 1965. An insulated single conductor is carried within a plastic channel strip inserted into a trough of a structural member. A lamp assembly includes a pointed portion for piercing the conductor to establish a first electrical connection with the ground connection being effected by means of screw members mounting the lamp to the quarter panel.
U.S. Pat. No. 3,231,731, was issued to McDonald on Jan. 25, 1966, and is entitled "Low Voltage Electrical Connector". The patent discloses a system of low volatge outdoor lighting using a two conductor cable with the lamp fixtures provided with a rear surface having portions of the lamp conductors thereon, each conductor portion having a bent corner for forming a prong, with each prong at a position for penetrating the insulation of one of the conductors. Clamping and piercing is effected by a clamp member configured for engaging side walls attached to the fixture for enabling tilting and attachment of the clamp while exerting force to urge the cable against the prongs.
In U.S. Pat. No. 3,248,576, entitled "Electrical Wiring and Conduit Assembly", issued to Russell on Apr. 26, 1966, there is disclosed an electrical distribution system for providing 120 volt and 240 volt power throughout a residence by the use of multiple conductors within a conduit configured as a baseboard, with electrical receptacles attachable thereto.
Another vehicle system is shown and described in U.S. Pat. No. 3,321,732, entitled "Marker Lamp Adapted for Mounting on an automotive Vehicle, and Connection into an Electrical Circuit, Without Use of Tools", which was issued to Goldbaum on May 23, 1967. In accordance with the disclosure, a quarter panel of the vehicle is configured with a channel including an electrical conductor with the lamp base configured for engaging a lip formed within the channel, which then enables pivoting of the lamp. A pointed conductive member on the lamp pierces the conductor for establishing the "hot" connection, with ground being effected by a spring member.
U.S. Pat. No. 3,341,802, entitled "Adjustable Mounting for Vehicle Lights", issued September 12, 1967 to Baldwin et al, and discloses another vehicle system employing a channel with a lamp assembly insertable therein with piercing means for providing electrical contact.
U.S. Pat. No. 3,391,377, entitled "Electrical Distribution System", issued July 2, 1968, to Corl et al, and discloses a suspended lighting system using a suspended rigid inverted generally U-shaped conduit with specially constructed conductors therein. A power plug is inserted into the open end and rotated ninety degrees, with prongs for providing electrical connection. A clamp is used to retain the plug on the conduit and to force the prongs through the insulation.
Another vehicle lamp system is shown and described in U.S. Pat. No. 3,451,035, issued to Baldwin on June 17, 1969, such patent being entitled "Rail Mounting Bracket for Vehicle Lamps". The rail is channel shaped with the lamp assembly inserted into the rail by one edge and then pivoted into position, with a coacting pronged connector piercing the insulation of a conductor within the rail.
Another variation of the above Baldwin vehicle lighting system is shown.and described in U.S. Pat. No. 3,474,381, issued Oct. 21, 1969 to Baldwin for "Lamp Connection and Mounting Devices".
U.S. Pat. No. 3,489,981, entitled "Electrical Distribution System", issued Jan. 13, 1970, to Corl et al, and is related to the above-described U.S. Pat. No. 3,391,377 of Corl.
The foregoing prior art is representative of the state of the art in flexible distribution and lighting systems, particularly those employing some form of conductive piercing means in a connection device for penetrating the insulation on an insulated conductor. Such prior art systems, particularly those of the type shown and described by Corl et al, require a rigid metallic generlly fully enclosed conduit with specially constructed conductor arrangements and brackets secured to the conduit with fasteners, such as bolts and the like. Similarly, the prior art of vehicular side lighting does not readily lend itself to residential, commercial and industrial lighting.